I have been a musician for many years now and over the past few years the net has completely revolutionised the reach and availability of my music.
I have been very happy to date with the exposure that social networking sites have opened up to me, my only annoyance was how restrictive sites like myspace are with content.
The recent trend has been to give out widget codes to users and fans can post content on private sites, blogs and emails.
This new widget by reverbnation.com is by far the best I have seen to date.
Information
The mother of all widgets.

Featuring a customizable picture, band info, music player loaded with your songs, a video, show schedule (with tour map), "join the mailing list" Fan Collector, and more.
You can also cross-promote other artists at the bottom of the widget. These artists are pulled from the list of artists you recommend, and rotated randomly. Great for helping out friends, label-mates, touring partners, or other artists you think your fans would enjoy.”
Here is an example of one of mine in action.

http://ephemera.audiomaker.net/example.html
You can get one yourself at
http://www.reverbnation.com
Good luck spreading the word.
James.